Speaker
Description
We analyze the finite-temperature equation of state (EOS) within the framework of an effective Lagrangian, where a dilaton field encodes the breaking of scale invariance in QCD. The present work extends a previous study in the pure gauge SU (3)c sector [1], in which the dynamics of the gluon condensate are described through a dilaton Lagrangian. Below the critical temperature, the condensate is dominated by the dilaton field, while above it, it evaporates into quasi-free gluons. As a new feature, we incorporate for the first time the lightest excited glueball, i.e. J = 2, into the thermodynamic description, assuming its mass lies on a linear Regge trajectory. The mass of the excited glueball is further affected by a string tension term. In this context, we investigate the impact of thermal fluctuations of the dilaton field by employing the method developed in Refs. [2, 3], which has been shown to reproduce lattice QCD results for thermodynamic quantities such as the pressure and energy density. We further extend the analysis to an EOS that includes additional hadronic degrees of freedom, namely the σ, π, ω, and ρ mesons, as well as nucleons, at finite chemical potential. This extension is realized within an effective Lagrangian that incorporates both spontaneously broken scale symmetry and explicitly broken chiral symmetry. Going beyond the mean-field approximation, we include the effects of thermal fluctuations of the scalar glueball and of the mesonic fields to gain further insight into the thermodynamic properties of the phase transition.
References
[1] A. Drago, M. Gibilisco, and C. Ratti, “Evaporation of the gluon condensate: a model for pure gauge su(3)c phase transition,” Nuclear Physics A, vol. 742, no. 1, pp. 165–181, 2004.
[2] G. W. Carter, O. Scavenius, I. N. Mishustin, and P. J. Ellis, “Effective model for hot gluodynamics,”Phys. Rev. C, vol. 61, p. 045206, Mar 2000.
[3] A. Mocsy, I. N. Mishustin, and P. J. Ellis, “Role of fluctuations in the linear σ model with quarks,”Phys. Rev. C, vol. 70, p. 015204, Jul 2004.
